ContentsFill: Table of Contents Across Tabs

ContentsFill is an add-on for Google Docs™ that makes a table of contents for every tab of a document: each tab and its headings, nested tabs under their parent, every heading linked.

Outline sidebar: every tab and its headings in a sidebar. Click a heading to go to it, in whichever tab it is. Free, as often as you like: headings for the first 3 tabs, and every tab listed.
Linked contents table: inserted where the cursor is, listing the headings of every tab, Heading 1 down to the level you choose, under each tab’s title. A click on a heading jumps to it in the same browser tab, in whichever document tab it is. After you edit, Refresh rewrites the same table in place.
Bookmarks at your headings: in Docs, a link to a heading in another tab goes to a bookmark, so ContentsFill puts one at the start of each heading the table lists. Docs shows a small blue bookmark marker beside each of them while you edit; the markers do not print. Remove table and bookmarks takes out the table and every bookmark ContentsFill added.

Not in this version: heading numbering.

Plans

Free: the outline with headings for the first 3 tabs, unlimited, and 3 contents tables or refreshes in total per Google account.
ContentsFill: $9 once per Google account for unlimited tables and every tab’s headings in the outline. No subscription. Refunds within 14 days. See the terms.

Install it from the Google Workspace™ Marketplace, then open it from Extensions > ContentsFill in any document.

Add-on will not open or uses the wrong Google account?